Tektronix 071-0590-00 Selecting the Active Pattern, Selecting Prbs Patterns, Word Patterns

Reference

The PRBS patterns generated and analyzed by the GB1400 are listed below.

Table 3-1. PRBS (2n-1) Test Patterns

n	Label Used in Generator	Length	Maximum Number of
	and Analyzer Displays	(2n-1 bits)	Contiguous 0s
7	PN 7	127	6
15	PN 15	32767	14
17	PN 17	131,071	16
20	PN 20	1048575	19
23	PN 23	8388607	22

Word Patterns

Word patterns are programmable by the user. Word patterns can be designed to cause specific stress characteristics, such as maximum jitter, or to simulate framed patterns like SONET, SDH, or FDDI. The standard GB1400 Generator and Analyzer will allow you to create and save up to ten 16-bit (two-byte) WORD patterns in battery-backed memory. Or, with the 1-Mbit Option installed, you can create and save up to ten 64 kbit WORD patterns (depends on buffer settings) in battery backed memory. Note that the standard and 1-Mbit instruments also store the current WORD pattern in battery-backed memory.

Selecting the Active Pattern

In this User's Guide, the pattern currently being generated by the Generator or analyzed by the Analyzer is called the active pattern. Procedures to make a selected PRBS or WORD the current active pattern are provided below.

Selecting PRBS Patterns

To select a PRBS pattern:

Press the PRBS key. The instrument will now be in the PRBS pattern mode.

Press the pattern up/down keys until the name of the desired PRBS pattern is displayed. Available PRBS patterns are:

PN 7

PN 15

PN 17

PN 20

PN 23

The displayed PRBS pattern becomes the active pattern immediately.

Selecting the Current Word Pattern

To make the current WORD pattern the active pattern, simply press WORD key.

GB1400 User Manual 3-3